# L45 — reachable landmark chamber

## Design and stamps

The SW demo opens through a rounded, side-facing ellipsoid portal, then follows a bent rock ramp with two level landings into the 17 × 15 m chamber. The sloped section drops 5.85 m; the maximum measured grade is 14.039°. An ellipsoidal rock dais rises 1.138 m above the chamber floor.

The demo layout resolves 166 version-2 stamps: 57 ellipsoid carves, 107 support pillars, and two filled ellipsoids for the floor and dais. The side portal and supported arrival landing are runtime-only under the demo flag. `owner_world.json` is unchanged.

## Reachability and shape audits

The surface search joins walkable ground near the arrival mouth to the chamber floor. The capsule route passed 66 samples and 6,798 clearance checks: zero blocked samples, zero unsupported samples across 330 support checks, and zero grade failures. Minimum clearance is 0.085 m. The exact buried L43 layout fails the same reachability audit as required.

L37 thresholds (planar patch <0.50 m², straight run ≤0.75 m, no sharp corners): the portal measured 0.417 m² / 0.522 m / 0 corners; the dais measured 0.282 m² / 0.750 m / 0 corners.

## Hashes and cost

- Source stamp: `0ec9177748faff6ef4813af0c418057edfcacf95c7c39c1292288a29c7775015` (GCC and Clang).
- Owner JSON SHA-256: `7b095f9bcc6b90133d5a463f99f0b571133b2c549ce1ecf2d64fe9175e41e183`.
- Demo-off layout IDs: FI `b7a7d9ecc48d8f26`; SW `8a52e84c26ed92d2`. The 12-hash W1/W12 owner signatures match L44: FI `9820f4f38b189b3f7263810e7b3ff62aa502b21f476ffcfdbc7761a65cb07d58`; SW `a1e9268a4bbcc77d2a1ac54095df6851a70bab65c43ae50b332ed75132617834`.
- Five-pair demo-off cost vs L44: FI median 16.476 → 16.677 s (+1.22%); SW 1.733 → 1.731 s (−0.12%).

## Verification and captures

`verify.py fast`, `medium`, and `full` passed in 189.5 s, 561.8 s, and 1,609.1 s. Passage, interface/hole, seeded random-camera, W1/W8/W12 determinism, and 30-cell checks passed.

All four JPEGs pass `capture_quality.py` and are under 300 KB:

- [Ground entrance, eye height at 7.03 m](captures/ground-entrance.jpg) — 36,041 B
- [Entrance looking in](captures/entrance-looking-in.jpg) — 41,507 B
- [Inside toward the dais](captures/inside-to-dais.jpg) — 36,590 B
- [Overview of entrance and chamber](captures/overview-entrance-and-chamber.jpg) — 58,255 B

## Failed runs

Six geometry trial exports were used, within the 15-trial budget. The boxy arch exceeded the shape limits; early ramp/support variants blocked the path or exceeded the grade limit; a deeper mouth cut broke the surface connection and was reverted. Early eye-level camera angles were wall-blocked or poorly framed. The first final fast invocation rejected a stale GCC stamp; GCC was rebuilt to match and fast passed. The buried L43 and deliberate verifier negative controls fail as expected.

## Orchestrator review (Claude)

Accepted as the flagged demo. The stamp matches the final Clang and GCC builds (`0ec91777…`); demo-off owner
hashes are identical to L44; the buried L43 layout fails the new reachability audit. The overview reads as a real
place: a sinkhole and curved path cut into the ground, leading down into a chamber with a rock dais. Not yet natural:
- **The ramp is visibly segmented.** Evenly spaced ribs run along it in the overview and the entrance view, the same
  per-segment seam family as the L35 ribs and L36 washboard. It is built from 57 carves plus 107 support pillars.
- **The ramp's raised edge has straight vertical walls,** so in `entrance-looking-in.jpg` it reads as a built walkway.
- **Headroom along the path is tight:** 0.085 m minimum clearance.
- The dais is a smooth dome, readable but plain.

Next (L46): replace the stamped ramp with one continuous floor-capped tunnel edge, following R12's first slice.